Learn how to measure the work required to increase the velocity of an object’s motion in this physics experiment. Understand the relationship between force, distance, and work done using a simple machine. Discover the impact of different factors on work and explore the principles of energy transfer. Find out how to convert measurements and grasp the concept of joules as the unit of work. Enhance your understanding of physics through hands-on experimentation.
SCIENCE – “ Work” is a term used in physics to signify that a force has caused an object to move. An example of work is when a tennis player hits a tennis ball with a racket, as the tennis ball moves when struck by the racket. However, work does not occur every time a force is applied.
For instance: when we push against a building for several minutes, we might become tired, but no work is done. This happens because the building does not move. The amount of work done is determined by multiplying the force acting on an object by the distance the object moves in the direction of the force. The SI unit for work is joule, where the SI units for force and distance are newton and meter, respectively. In this experiment, you will learn how to measure the work done on an object and determine the effect of a simple machine on work.
Learning Objective
The experiment aims to measure the amount of work required to increase the velocity of an object’s motion.
Materials
- Brick (or similar object with nearly the same weight)
- Shoebox large enough to hold the brick
- Punch hole paper
- Spring balance with hook, maximum capacity 2200 grams
- Wooden meter stick
- Insulation
Procedure
- Place the brick inside the shoebox.
- Use the punch hole paper to create a hole at one end of the box. Insert the hook from the spring balance through the hole (refer to Figure).
- Position the box at one end of the table. Attach insulation measuring 15 cm horizontally in front of the box. This insulation will serve as the starting line.
- Measure the distance from the starting line to the edge of the table in meters (m) – the SI unit for distance. Record this as the distance traveled (d) in the Data Table for Work, as shown in Table.
- Pull the spring balance so that both the balance and the box move horizontally across the table at a constant speed. Read the scale on the spring balance when the box crosses the starting line. The force must be measured in newtons (N) – the SI unit for force. Record the force in newtons in the Data Table for Work. If using pounds, convert pounds to newtons using the conversion: 1 pound = 4.45 N. For example, if the measurement is 2 pounds, the force in newtons is 2 pounds x 4.45 N/1 pound = 8.9 N. If the unit is in grams, convert grams to newtons using the conversion: 1 g = 0.0098 N. For instance, if the measurement is 908 g, the force in newtons is 908 g x 0.0098 N/1 g = 8.9 N.
- Repeat Step 5 four times and calculate the average of the measurements.
- Calculate the work done on the box using the equation: w = F x d. In this equation, w represents work, F is the force applied to the box in newtons, and d is the distance (in meters) traveled by the box while the force was applied. For example, if F = 8.9 N and d = 0.5 m, then w = 8.9 N x 0.5 m = 4.45 Nm.
Note: 1 Nm = 1 joule (J). Joule (J) is the SI unit for work. So, in this example, the work done is 4.45 J.
Results
The amount of work done depends on the force needed to pull the box and the distance it travels while in motion. In this case, the work done is 4.45 J.
Why?
Work is achieved when a force causes an object to move. The magnitude of work done is the product of the force applied to an object and the distance the object moves in the direction of the force. Another requirement for work to occur is that the distance traveled by the object must be in the same direction as the force applied. In this experiment, the horizontal force applied causes the box to move horizontally, resulting in work being done.
Try a New Approach
- Does the velocity of the object’s motion affect the amount of work required to move it? Repeat the experiment twice: first at a higher constant velocity and then at a lower constant velocity.
- How does the weight of the moved object affect the work needed to move it? Repeat the initial experiment twice: once with a lighter load inside the box and once with a heavier load. Note: Try to maintain the same pulling speed for each trial.
